The Orbital Index

SpaceX does EVA. To mark one of space fans’ favorite days of the year, SpaceX unveiled the next major iteration of development from its spacesuit program (promo video). The new SpaceX EVA suit, in tandem with an updated Crew Dragon capsule, will perform the first commercial extravehicular activity as part of the Polaris Dawn mission (overview of the mission, as well as Dragon modifications and EVA suit design). SpaceX’s new suit borrows material expertise from other existing programs within the company and heavily focuses on the upper body for the moment since lower body mobility isn’t as high a priority during EVAs. The shoulders and forearms of the suit feature semi-rigid joints (soft at low pressure, hard smoothly rotating joints when pressurized) with additional flexures at wrists, elbows, waist, and legs. Designed to be worn both inside (IVA) and outside (EVA) of the capsule, the suits will feature a slow zero-pre-breathe transition to 0.35 bar pure oxygen to avoid decompression sickness/the bends during the ~2-hour EVA (when the entire capsule will be exposed to vacuum). Suits are pressurized to a full 1 bar during ascent and re-entry, but use a mix of nitrogen and oxygen due to the lessons learned from Apollo 1 (Apollo missions also continued to use pure oxygen while in space, just not at pressures above ~0.4 bar). This version of the suit will require an umbilical for temperature management, life support, and power—in the future SpaceX hopes to merge its IVA and EVA suits into a single architecture that could support autonomous operation. Polaris Dawn is scheduled for later this summer and will also test Starlink-to-Dragon laser links, gather data on space radiation’s impact on humans (it is targeting a record 1,400 km apogee for a crewed Earth-orbit mission, just inside the Van Allen Belts), and perform 40+ experiments over 5 more days of the mission. 

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• At the end of their lives, Sun-like stars balloon out into red giants, likely consuming any inner planets, and then eventually expel most of their stellar material, leaving behind a slowly cooling white dwarf star. (If we’re still around, we’ll need to move the Earth out of the way.) It is thought that outer planets could survive the red giant phase (and even that new planets might form out of expelled stellar material), but until now planets hadn’t been directly imaged around white dwarfs. A new paper describes a result from JWST showing what look like two directly-imaged Jupiter-like planets orbiting around white dwarf stars. The stars are also “polluted” with metals, perhaps the result of the red giant phase’s consumption of the systems’ inner planets.
• Another polluted white dwarf, about 63 light-years away, sports the signature of a localized metallic scar on its surface. This scar is thought to be where a Vesta-sized (~500 km in diameter) metallic asteroid crashed into it in the recent past (paper).
• Data from Curiosity’s ChemCam shows surprisingly high amounts of manganese oxide in lakebed rocks within Gale Crater on Mars, suggesting formation in a very wet and oxygen-rich environment (paper). On Earth the formation of manganese oxide is facilitated by our biologically-produced oxygen-rich environment and often microbes catalyzing manganese oxidation. “The Gale lake environment, as revealed by these ancient rocks, gives us a window into a habitable environment that looks surprisingly similar to places on Earth today. Manganese minerals are common in the shallow, oxic waters found on lake shores on Earth, and it's remarkable to find such recognizable features on ancient Mars.”
• Based on the ratio of two isotopes of sulfur which are fairly constant throughout the solar system, researchers studying the element in the atmosphere of Io determined that the volcanic moon has lost ~95% of its initial sulfur due to eruptions (paper). If current depletion rates are representative, this implies that Io has been erupting for billions of years, supporting evidence that the moons of Jupiter, including Io and Europa, have been in their current, heat-inducing gravitational dance since the early solar system. This could be good news for the possibility of a long-term habitable subsurface ocean on Europa.
• By comparison, measurements of Saturn’s moon Mimas’s wobbly orbit and rotation indicate that it may have a 30 km deep tidally-heated ocean hiding under its icy surface (paper). “But it seems to be a young ocean — having formed in the past 25 million years. [...] If the ocean had been around for longer, it would have begun to exert its influence on Mimas’s icy surface by now, for example by fracturing it. [Until recently], Mimas was probably traveling on a stretched-out orbit that caused it to gravitationally interact with other Saturnian moons. That tidal interaction would have heated up Mimas, melting its interior and creating the ocean.” Related: The coolest moons of Jupiter and Saturn you've never heard of.

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• Speaking of the volcanic moon, Juno recently delivered new observations of Io. “We also got some great close-ups and other data on a 200-kilometer-long (127-mile-long) lava lake called Loki Patera. There is amazing detail showing these crazy islands embedded in the middle of a potentially magma lake rimmed with hot lava. The specular reflection our instruments recorded of the lake suggests parts of Io’s surface are as smooth as glass, reminiscent of volcanically created obsidian glass on Earth.”
• Meta and World Resources Institute recently released a global map of tree canopy height at a 1-meter resolution, sufficient for detecting single trees. The underlying imagery is 0.5m data from Maxar. Earthblox has a review of their approach.
• XPrize announced the 20 qualified finalist teams for their Space-based Wildfire Detection and Intelligence track. Familiar names include Muon Space, Loft, and Orbital Sidekick, among others. “[T]eams will have one minute to accurately detect all fires across a landscape larger than entire states or countries, and 10 minutes to precisely characterize and report data with the least false positives to fire managers on the ground.”
• Psyche (the spacecraft) is now ~2 AU from Earth. Last month, the craft again tested its deep space optical comms demonstration hardware (cf. Issue 238), transmitting over 226 million kilometers. Target data rates of 1 Mbps were far exceeded, with duplicated mission data (a first, previous test had been with preloaded test data) being sent at a blistering 25 Mbps. DSOC is being developed with an eye toward future high data rate Mars communications needs.
• The US Space Force found a dead Cold War-era satellite that had been “lost in space” for 25 years.
• JP Aerospace’s Airship to Orbit project, is the minimalist website of a small project that’s been running for over 25 years. JP Aerospace is a 42-year-old, volunteer-led, “independent space program.”